That's really an impressive flame setup. Anyway, Hhoffman, your benchmarks have shown that I'm doing something wrong, and there's room for improvement, since we have a fairly comparable hardware, would you know why I'm not getting the same throughput as yours?

Or roughly 73.37 MB/s (the test file was 46936088000 bytes/44761.7 megabytes, divided by 10m10s/610 seconds clock time). The test file was on a single U160 disk, so it might be possible to increase performance if the test file was read from an array of disks with higher throughput.

I used the same tape drive definition file in /master.d/scsi as hhoffman with the device info modified to match the Quantum drive used:

Or approximately 78.80 MB/s (46936088000 bytes/44761.7 megabytes, divided by 9m38s/578 seconds clock time). Slightly higher than the Quantum SAS, though the limiting factor in either case is likely the throughput of single U160 hard drive. I have an external SATA hard drive enclosure that holds up to eight disks. Strictly consumer grade stuff when it comes to things like redundant data storage or even redundant power supplies, but it's desktop quiet (magnitudes quieter than the typical enterprise storage array) and relatively inexpensive to purchase / run. Did I mention it's *quiet* .

So I'd like to test the SAS tape drives against desktop SATA array, but first I'll have to resolve a few SAS controller issues.

The SAS controller I'm using is an LSI SAS3800X with two external SFF-8470 ports (the tape drives are both in a 2U rack enclosure, each drive has an external SFF-8088/miniSAS connection).

Initially had some issues with the SAS3800X until I isolated it as the only PCI device in the slave O350. If I connect to both ports on the SAS3800X it results in fatal PCI_Bridge errors. After doing some research I'm pretty sure I can resolve the won't pci-bus cohabitate / pci bridge errors by updating the firmware on the SAS3800X. Unfortunately I can't flash the board from IRIX. lsflash just hangs there without returning the prompt. For anyone else who might consider trying this, I'll mention I was running lsflash against firmware d/l'd from LSI - a process *not* recommended unless you're willing to accept the risk of bricking the controller. I chose to try it because while man lsflash does mention using lsflash with LSI's 1064/1068 controllers, SGI doesn't include 1064/1068 firmware (in /usr/firmware/ls).

So I'll have to temporarily put the project on standby until I get access to a PC with 3.3V PCI-X slots.

Got the firmware on the LSI controller reflashed. That seems to have resolved the issues with PCI_Bridge errors and conflicts with other PCI devices.

With the firmware issues resolved the LSI SAS controller was installed in a Tezro to see if the differences in PCI bus speed had an effect on performance (the PCI busses in an O350 limit PCI devices to a maximum of 100MHz, while the Tezro doesn't limit 133MHz PCI devices):

Not sure if the increase in performance is due to the firmware, the faster PCI bus, or a combination of both, but the difference was noticeable: 91.91 MB/s (46936088000 bytes/44761.7 megabytes, divided by 8m7s/487 seconds clock time).